In recent years, with the widespread use of mobile phones, interests in personal mobile communication are increasingly developing. Accordingly, forms in which a card-shaped communication card is attached to an already-spread information device having a card slot, such as notebook personal computers, personal digital assistances (PDA) and digital cameras, are suggested, and various communication cards are provided for that purpose.
FIG. 16 is a diagram schematically showing a usage form of a conventional communication card. A communication card 1102 is constituted by a connector portion 1104, a card portion 1105, and an antenna portion 1106.
In FIG. 16, the communication card 1102 is inserted into a card slot 1103 of an information device 1101, and then the connector portion 1104 of the communication card abuts a connector of the information device, thereby being attached thereto. Here, the communication card 1102 is housed in the card slot 1103 from the side of the connector portion 1104 up to the boundary area between the card portion 1105 and the antenna portion 1106. The antenna portion 1106 protrudes from the card slot 1103 so as not to deteriorate the antenna capability.
Further, FIG. 17 is a block diagram illustrating a communication card.
As shown in FIG. 17, a communication card is constituted by a transmitting/receiving antenna 1107 for transmitting/receiving communication waves, an amplifier 1108 for amplifying a signal, a frequency converter 1109 for converting a frequency of an inputted signal, a modulator/demodulator 1110 for demodulating a received signal or modulating a signal to be transmitted, a baseband processor 1111 for processing a baseband signal, and a card interface 1112 for communicating data with an information device.
When the communication card 1102 receives communication waves, a received signal flows in a following order: received signal (radio waves)→the transmitting/receiving antenna 1107 (operating as a receiving antenna at the receiving)→the amplifier 1108→the frequency converter 1109→the modulator/demodulator 1110 (operating as a demodulator at the receiving)→the baseband processor 1111 the card interface 1112. When a signal is transmitted from the communication card 1102, the signal to be transmitted flows in a following order: the card interface 1112→the baseband processor 1111→the modulator/demodulator 1110 (operating as a modulator at the transmission)→the frequency converter 1109→the amplifier 1108→the transmitting/receiving antenna 1107 (operating as a transmitting antenna at the transmission)→the signal to be transmitted (radio waves).
However, this communication card 1102 has such a construction that the antenna portion 1106 protrudes from the body of the information device 1101 when the communication card 1102 is inserted into the information device 1101. Thus, when the information device 1101 is carried out with the communication card 1102 being attached thereto, the antenna portion 1106 protruding from the body is put in an easily touched state, thereby having a risk of breakage, and further becomes an obstacle when carried out.
To prevent the protruding part from being an obstacle, there has been conceived that the antenna portion 1106 is miniaturized as a part of the card portion 1105 to decrease the protrusion from the body. However, with the above-mentioned construction of the conventional communication card 1102, when the protrusion from the body is decreased, the metallic body of the information device 1101 and the antenna electromagnetically couple with each other, thereby deteriorating the antenna characteristics, resulting in a degradation of the communication functions. Further, while the communication card 1102 is generally employed being replaceably inserted into various information devices 1101, the degrees of the electromagnetic coupling between the information device 1101 and the communication card 1102 vary with the information devices 1101 to be used, so that the degree of the coupling cannot be predicated in advance, which makes the solution of the problems more difficult.
Further, to make the antenna portion 1106 harder to be broken, a solution in which the connection between the antenna portion 1106 and the card portion 1105 is made solid, and a solution in which the antenna portion 1106 is enabled to be detached using a high frequency connector are examined. However, when these solutions are performed, manufacturing costs for the communication card 1102 are unfavorably increased.
The present invention is made to solve the above-mentioned problems, and has for its object to provide a communication card and a communication device which can prevent the breakage of the antenna portion and the deterioration of the antenna characteristics, and further can suppress increases in the manufacturing costs.